The present invention relates generally to the fabrication of laminated products like motor vehicle tires, more specifically to drum-transfer techniques for building such products, and still more specifically to drum-transfer techniques for assembling narrow components onto a building drum, particularly in the context of an automatic tire building system having a sequence of work stations,.
The manufacture of laminated rubber and synthetic rubber products like tires and drive belts is commonly accomplished using a drum-transfer building technique. This technique involves the use of a xe2x80x9cbuilding drumxe2x80x9d on which components of the product are assembled, and a number of xe2x80x9cmeasuringxe2x80x9d or xe2x80x9cmeasuringxe2x80x9d drums from which components of the product are transferred to the building drum. Each component of the product is initially placed onto the surface of a measuring drum at a xe2x80x9cwork stationxe2x80x9d and is cut to the right length. The measuring drum is then moved towards the building drum until the component contacts the building drum. The rotation of the building drum with respect to the measuring drum causes the component to transfer from the measuring drum to the building drum. An example of a measuring drum is disclosed in U.S. Pat. No. 4,504,337. In an automatic tire building system, such as disclosed in U.S. Patent Application entitled METHOD FOR MANUFACTURING TIRES ON A FLEXIBLE MANUFACURING SYSTEM, Attorney""s Docket No. DN2001166USA, the building drum travels from work station to work station, receiving one or more components at each work station until the product (or a subassembly thereof) is completed on the building drum. In this tire building system, a plurality of building drums are employed in xe2x80x9cpipelinexe2x80x9d fashion such that at any given time there are building drums in process at different work stations or in transit between stations, each drum serially acquiring product components.
This drum-transfer process is shown schematically in FIGS. 1A-1C. FIG. 1A shows a drum-transfer assembly portion 10 of a work station wherein a measuring drum 12 has had a tire component 14 placed on the surface thereof and the component 14 has been cut to length. A building drum 16 is in position, spaced away from the measuring drum 12, awaiting transfer of the product component 14. The measuring drum 12 and building drum 16 are placed in contact with each other, as shown in FIG. 1B. The measuring drum 12 and the building drum 16 are rotated in coordination with one another to cause the component 14 to release from the measuring drum 12 and adhere to the building drum 16. Once the transfer of the component 14 to the building drum 16 is complete, the measuring drum 12 and building drum 16 are spaced from each other in preparation for receiving a new component 14, as shown in FIG. 1C.
Typically, one or more tire components 14 are applied to the building drum 16 from the measuring drum(s) at each work station. When two of the same type but spaced tire components are assembled onto the tire building drum at the same work station, it has been difficult to apply them both at the same station, especially when the two spaced-apart narrow components 14 are close to each other. An example of applying two components is the assembly of two tire inserts of a runflat tire, wherein the two insert components are transferred to the building drum from two measuring drums at the same work station.
A two-component assembly technique of this type is illustrated schematically in FIG. 2. FIG. 2 shows a top view of a portion 10A of a two-component work station comprising a pair of narrow measuring drums 12A and 12B positioned side by side, each having been prepared with a respective tire component 14A and 14B, such as tire insert components, for transfer to a waiting building drum 16.
Two-component assembly at a single work station has at least two significant advantages over single component assembly: speed of assembly and conservation of manufacturing floor space. Multiple component assembly, however, is limited by the number of measuring drums that can be positioned side by side in a work station and by the position of the components within the product. If the components must be placed very close to one another on the building drum, it is not possible to position two measuring drums closely enough together in a side by side configurations to place both components in their correct positions.
It would be advantageous, however, if there were a way to assemble multiple, narrow, closely-spaced components of a tire construction onto a tire building drum at the same work station, since the size and cost of separate work stations and additional assembly time is disproportionate to the size, cost and value of some narrow components.
As an example, where several narrow components, such as a bead filler and a support strip are both located in the bead area of a vehicle tire are narrow, it is possible to assemble the two bead filler components at one work station and the two narrow support strips at another work station. Using prior-art techniques it is not possible, however, to assemble the both the support strips and the bead filler components at the same assembly station, since the bead filler component is assembled at least partially on top of the support strip component, preventing the use of side by side measuring drums.
In view of the aforementioned difficulty in assembling multiple, closely-spaced, narrow components at a single work station, and in light of the clear advantages of doing so, there is an ongoing need for improved drum-transfer assembly techniques.
According to the invention, multiple components are assembled onto a building drum at a work station by providing measuring drums that are independently controllable in two dimensions: laterally (parallel with respect to the building drum axis of rotation) and longitudinally (perpendicular to the building drum axis of rotation). A first set of measuring drums is positioned laterally to the inside of a second set of measuring drums such that they can be moved independent of one another without collision. Generally speaking, the first and second sets of drums travel alternately between first and second transfer positions, respectively, adjacent the building drum, first and second ready positions slightly spaced from the building drum and first and second component loading positions, respectively. When the first set of measuring drums is at the first component loading position receiving new tire components, the second set of measuring drums is positioned at the second ready or second transfer position near the building drum. The first set of measuring drums is retracted (longitudinally) from the first transfer and first ready positions to the first component loading position while the second set of measuring drums travels outside of the first set of measuring drums to a second ready position and finally to a second transfer position adjacent the building drum to apply components onto the building drum. When the first set of measuring drums moves from the first ready position to the first loading position, new components are applied thereto. After transferring components from the second set of measuring drums to the building drum, the second set of measuring drums are retracted from the second transfer position to the second ready position and finally to the second loading position while the first set of measuring drums is moved back to the first transfer position as described before. After the components are applied to the tire building drum, it moves on to a next work station, a new building drum is moved into position in the work station, and the cycle begins again.
When a set of measuring drums (first or second set) arrives at the first or second ready position adjacent the building drum, they are positioned laterally to clear the other set of measuring drums, and must be repositioned laterally to assemble their tire components onto the building drum in the correct position. After transferring the tire components to the building drum, the set of measuring drums move back to their respective first or second ready position and once again repositioned laterally to clear the other set of measuring drums in travel back to their respective loading positions.
According to a method aspect of the invention, multiple components are assembled onto one or more tire building drums by providing first and second sets of measuring drums, and providing first and second sets of components on the first and second sets of measuring drums, respectively. The first set of measuring drums is positioned into a first ready position adjacent the tire building drum and the second set of measuring drums is positioned in a second loading position. Then the first set of measuring drums is retracted away from the tire building drum to a first loading position and the second set of measuring drums is moved around the first set of measuring drums to a second ready position adjacent the tire building drum.
According to a further aspect of the invention, the first set of components is transferred from the first set of measuring drums to the tire building drum by moving the first set of measuring drums from the first ready position to a first transfer position.
According to a further aspect of the invention, the second set of components is transferred from the second set of measuring drums to the tire building drum by moving the second set of measuring drums from the second ready position to a second transfer position.
According to a further aspect of the invention, a new first set of components is applied to the first set of measuring drums while the first set of measuring drums is in the first loading position.
According to a further aspect of the invention, a new second set of components is applied to the second set of measuring drums while the second set of measuring drums is in the second loading position.
According to another aspect of the invention, the tire building drum is moved into a work station from a previous work station prior to assembling either first or second set components thereto.
According to another aspect of the invention, the tire building drum is moved from the work station to a next work station after assembling first and second set components thereto.
According to another method aspect of the invention, multiple component assembly onto a tire building drum having an axis of rotation located at a work station. The method involves the steps of:
providing a building drum having an axis of rotation at the work station;
providing a first set of inner measuring drums with axes of rotation parallel to the axis of rotation of the building drum, each inner measuring drum being independently movable parallel to and perpendicular to the axis of rotation of the building drum;
disposing a first set of components on the first set of inner measuring drums;
providing a second set of outer measuring drums with axes of rotation parallel to the axis of rotation of the building drum, each outer measuring drum being independently movable parallel to and perpendicular to the axis of rotation of the building drum;
disposing a second set of components on the second set of measuring drums
controlling the first and second sets of measuring drums to move between respective first and second loading positions and respective first and second ready positions adjacent the tire building drum such that the first and second measuring drums clear one another as they travel;
transferring the first set of components from the first set of measuring drums to the building drum; and
transferring the second set of components from the second set of measuring drums to the building drum.
According to an aspect of the invention, the first set of measuring drums are moved longitudinally towards the building drum from a first loading position inside of the second set of measuring drums, to a first ready position adjacent the building drum in preparation for transferring the first set of components onto the building drum.
According to another aspect of the invention, the second set of measuring drums are moved longitudinally towards the building drum from a second loading position outside of the first set of measuring drums, to a second ready position adjacent the building drum in preparation for transferring the second set of components onto the tire building drum.
According to another aspect of the invention, the step of providing a building drum at the building location comprises moving a building drum from a previous location to the work station.
According to another aspect of the invention, motion of the first and second sets of measuring drums is controlled so that they follow specific paths. Simultaneously, the second set of drums is moved laterally apart from one another at the second ready position and then longitudinally away from the tire building drum to a second loading position while the first set of drums is moved from the first loading position, longitudinally towards the tire building drum to a first ready position prior to transferring the first set of components to the tire building drum at the first transfer position. Then, simultaneously, the first set of measuring drums is moved back to the first ready position, laterally together, and then longitudinally away from the tire building drum to a first loading position while the second set of measuring drums is moved laterally outside of the first set of measuring drums and longitudinally towards the tire building drum to a second ready position adjacent the tire building drum prior to transferring the second set of components at the second transfer position to the tire building drum.
According to another aspect of the invention, new components are applied to the first and second sets of measuring drums while they are in their respective first and second loading positions.
The present invention also describes a work station for assembling multiple components onto a building drum at a work station, comprising a first set of measuring drums and a second set of measuring drums, a building location for receiving a building drum, the building drum having an axis of rotation, and independently controllable means for effecting lateral and longitudinal motion of each of the first and second sets of measuring drums.
Alone or in combination, the various aspects of the invention permit multiple, different types of components to be assembled on a tire building drum at a single work station, thereby saving production floor space, reducing assembly time, and lowering equipment and assembly costs.
The present invention is particularly useful in conjunction with a system for simultaneously building a plurality of tire carcasses, such as is disclosed in the aforementioned copending Patent Application entitled METHOD FOR MANUFACTURING TIRES ON A FLEXIBLE MANUFACURING SYSTEM, Attorney""s Docket No. DN2001166USA and described hereinbelow with respect to FIGS. 1A, 1B, 1C, 1D and 2. The method disclosed therein generally comprises the tire building steps of establishing a sequence of at least three and up to ten work stations; advancing at least three disconnected tire building drums along a working axis extending through the at least three work stations; and applying one or more tire components to the tire building drums at each of the work stations. Then the resulting green tire carcass is removed at the last of the work stations. Finally, the tire building drum is advanced from the last work station after the green carcass has been removed to the first work station.